PCIe Preps for Internet of Things

SAN JOSE, Calif. — The PCI Special Interest Group is exploring ways it can expand use of its interconnect in the Internet of Things and SoCs. Meanwhile, the PCI-SIG is moving ahead with its 16 GTransfer/s PCI Express Gen 4 and other specifications driving the link's current use primarily in servers.

"The server solution is locked and loaded with PCIe 4, so we want to see where else the technology can proliferate," Al Yanes, president of the PCI-SIG, told EE Times. "We want to get it into SoCs and IoT designs, where there will be some growth."

The group is already working on protocol extensions to make PCIe more friendly for SoCs designs. Modified addressing schemes that don't assume the relatively complex hierarchy of a PCIe root complex could help shrink on-chip hardware requirements and open up new uses, Yanes said.

More details on the group's plans are expected perhaps as early as the fall. The work goes beyond the M-PCIe, a version of the PCIe protocols for mobile devices running over the M-PHY of the MIPI group.

Meanwhile, engineers heard briefings on early details of PCIe Gen 4 at the annual PCI-SIG developer's conference here. The group expects to finish a 0.5 version of the spec this year and start lab work validating hardware based on it. A finished spec ready for use in products is slated for early 2016. It is expected to require a new connector design to carry traffic at twice the rate of today's Gen 3 link, hopefully over similar distances.

Separately, the group continues to make progress on two new PCIe connectors.

OcuLink is a copper cable for servers carrying four PCIe Gen 3 interconnects for up to 32 Gbit/s aimed at external I/O expansion or links to internal or external storage. The spec should be finished in time for products shipping at the end of the year, with an optical version still in the works.

SFF-8639 is a connector to link an array of solid-state drives (SSDs) to a backplane in a single sever or a rack-mounted server cluster. A 0.7 version of the spec was released in March.

Startup Fusion I/O was one of the early vendors to link SSDs to servers via PCIe -- an approach now widely used. "PCIe for attached storage is a booming business because the storage industry has recognized the benefits of PCI Express," said Yanes.

In gerenral, 10000 of IOTs will be connected to a server (Low-mid end). If we can increase the bandwidth and deploy high end servers, we can connect 0.1million to 1 million of IOTs per server. This will be huge saving from data centers perspective.

I think you hit it right on the head. Each device may only need a small amount of data but will billions of them, servers might be overloaded. In the end, IoT devices could consume more aggregate bandwidth than is needed for video, simply by the sheer numbers. Give it 20 years or so.

I agree. I speculate that IoT applications, from where the growth and volume would come from would mostly be needing "low power" and hence data rates would be lower. The focus should be low power and not speed, I think. In that context I don't know which IoT market is on radar of PCI SIG, where they see good growth. May be, for the servers, which would have large volume of data due to so many devices connected and that is where >32Gbps speed would be helpful?